Gas fired water heater



June 11, 1957 DNGES Erlu., 2,795,380

GAS FIRED WATER HEATER Filed Aug. 11, 195s z snow-Sheer 1 l 'Inventum TgM 2 Sheets-Sheet 2 Unvemors JM ff" f W M H. DNGES ETL GAS FIRED WATERHEATER June l1, 1957 Finding. 11, 195s 21,795,380 v Ice VPatented June1l, 195'? 2,795,380 GAS FIRED WATER HEATER Hans Dnges and Johannes Ptz,Remscheid, Germany,

assignors to `loh. Vaillant K.G., Remscheid, Nordrhein, Westphalia,Germany Application August 11,1953, Serial No. 373,647

6 Claims. (Cl. 236-25) i This invention relates'to a gas heatedcontinuous flow type hot water apparatus with a water deficiency safetydevice respondingy to the dynamic pressure dilerence.

As is known, such a water deficiency safety device automatically shutsoff the gas supply to the burner, as soon as the dynamic pressuredifference available at a throttle located in the cold water passage isequalized. This occurs when the hot water tap is closed, i. e. there isno more llow of water. Therefore, considering an inevitable retardationin response, the burner lames will only` extinguish, if there is no moreflow of water. The heat stored in the apparatus therefore must beabsorbed by the quiescent water, non-admissible heating up of this wateroccurs thereby which in turn tends to a depositing of boiler scale. Thisis in particular applicable to hot water apparatus having high flow-outtemperatures ranging near the boiling point.

This invention has for its object to dispense with these disadvantageousafter-heating phenomena.

According to the invention this object has been accomplished therebythat by the locking motion of the tap valve the dynamic pressurediierence is equalized temporarily at the throttling point, the waterdeficiency safety device being caused thereby to respond still beforethe ow of water is interrupted. Thus, the water deficiency safety deviceis caused to respond prematurely, while water is still flowing throughthe apparatus, so that after the gas burner has extinguished still afurther, possibly even increased flow of lwater takes place whichremoves the stored heat.

Several possibilities exist to obtain a temporary elimination of thedynamic pressure difference at the water deficiency safety device whilethe lwater flow is being maintained. This can be accomplished, forinstance, thereby that a channel by-passing the throttling point isconnected to the depression chamber of the safety device, the by-passingchannel being opened temporarily during the locking motion of the tapvalve. When opening this bypassing channel, the low pressure iseliminated and may even be converted into overpressure. This result canalso be obtained by providing a junction channel between the dynamicpressure chamber of the water deticiency safety device and the flow-outopening of the hot water apparatus. This junction channel is openedtemporarily during the closing motion of .the tap valve. The dynamicpressure effective aty the water deficiency safety device is therebyeliminated, so that the water deficiency device cornes to action. Y

To these and other ends the invention consists in the advantageousconstruction and arrangement which will appear clearly from thefollowing description when read in conjunction with the accompanyingdrawings wherein two embodiments have been represented as examples.

In the drawings:

Fig. l shows in 'schematical' representation a gas heated cording to theinvention,

Fig. 2 is a section through the diaphragm housing of the waterdeficiency safety device, and

Fig. 3 shows in schematical representation the lower part of a gasheated continuous flow type hot water apparatus of somewhat dierentdesign.

From the cold water supply designated by the numeral 1, the water entersthe pressure chamber 2 and through a flow regulator valve 3 enters thedynamic pressure chamber 4 of a water deficiency safety device which iscontrolled by a diaphragm 5. The dynamic pressure chamber 4 is connectedwith a Venturi tube 7 through a joining tube 6. Thus, the water can flowthrough the Venturi tube 7 yand through a conduit 8 to the heatexchanger 9, and from there through a tapping conduit 10 to a tap valve11 and to an auxiliary draw oif 12. Due to this ow of water, a dynamicpressure is produced in front of the Venturi -tube 7, i. e., in thedynamic pressure chamber 4. A low pressure is produced simultaneously inthe portion of the Venturiftube 7 having the most narrow cross section7, this narrow portion being termed suction space. A low pressureconduit 14 leads from the suction space of the Venturi tube 7 through acheck valve to the low pressure chamber 15 above the diaphragm 5.

A low resistance only is caused by the check valve 13 to v the ilow fromthe suction space 7' of the Venturi tube 7 to the low pressure chamber15 of the diaphragm controlled tap mechanism, while a great resistanceto fiow is caused by the check valve if the water ows in the oppositekdirection.

Pig. 2 shows clearly the structural set up of the valve 13. Thisvalve iscomposed of a valve disk cooperating with a valve seating. The valvedisk is provided with a small opening. A ow of water streaming from .thesuction space 7 of the Venturi tubef7 to the low pressure chamber 15 ofthe diaphragm controlled tap mechanism lifts the valve disk shown at 13,so that there is only a small resistance caused to such a ow by valve13. But a ow having opposed direction must force slowly through thesmall opening provided in the valve disk of the valve 13 and thereforehas to overcome a greater resistance to How. As longas one of the tapvalves 11 or 12 is open and therefore water is allowed to flow throughthe Venturi tube 7, the -diaphragm 5 is under the inluence of a dynamicpressure difference governing in the chambers 4 and 15. This pressuredifference causes the diaphragm to move upwards and'to open a I.gasvalve 24 against the action of a valve spring 24. If now the flow ofwater is throttled and consequently the pressure existing in the suctionspace 7 rises, a rapid equalization of pressure can then take place viathe Valve 13 and through the channel 14. If, however, a negativepressure is produced in the suction space 7 and water is sucked off fromthe chamber 15 when opening the tap valve 11 or 12, the valve will thenperform a braking action causing the diaphragm 5 to lift slowly and thegas Valve to open gradually only. As it is known, such a slow ignitionvalve has the purpose to avoid a large quantity of gas streamingimmediately to the burner and dea'grating when the always somewhatretarded ignition takes place.

The regulator valve 3 fastened to the diaphragm adjusts itself in such amanner that the pressure difference available at the diaphragm 5 is keptconstant even if llow of water should vary because of water supply linepressure variations.

A by-passing conduit 16 branches from the pressure chamber 2 and leadsthrough a control valve housing 17 and a branch conduit 16 to the lowpressure chamber 15. The conduit 16, 16' by-passes both the Venturi tube7 and the return valve 13, and as the conduit 16, 16 branches in frontof the regulator valve 3 located in the cold water supply line, anon-throttled stream of water is admitted to the low pressure chamber15.

A valve body 18 is guided in the `control valve hous ing 17 and ispressed on a valve seat 20 by means of a compression spring 19. Thespring 19 is supported by the valve body of the tap valve 11. Anotherspring V21 tends to press another valve'body` 22l tothe valve seat 2d,however, does not succeedfto close the valves 20/22, since it (Z1) isnot able to overcome the stronger spring 19. The valve body 22 restswith its valve spindle 22 in a bored hole 18' of the valve body 18. Withthe -tap valve 11 fully opened, the valve 22/20 is closed; with the tapvalve 11 fully closed, the .valve 18/20 is closed. However, the valvedisk 22y is lifted from its seating when the closing movement of the tapvalve 11 is almostcomplctcd, while the valve-disk 18 Adoes not yet reston its seatingv free.

In the represented locking position ofthe tap valve .11'

the by-passing conduit `16, '16 is closed by the valve 18/20, so thatthewater deficiency `safety device is enj` abled to put the apparatus incommon manner. to opera.-

tion when drawing off water at the auxiliary tap i2.' As describedabove, this is effected thereby that the daL phragm 5, under theinfluence of the dynamic. pressureV gas valve 24 is formed by the hollowcock plug of the A main gas cock and can be hand operated `by means of aWith the tap valve 11 opened, the by-passing cont lever. duit 16, 16 isclosed by the control valve 20/'22, as Ynow the spring 21 is enabled topress the valve body 22 on to the seat 20. Thus, the dynamic pressuredifference necessary for the above described operation of the apfparatus is also produced at the Venturi tube 7 when the tap valve 11 isopen.

If the tap valve 11 is closed,'both valve Abodies 18/22 are lifted bymeans of the spring 19 during the locking movement. The by-passingconduitvl, 16' is open when the tap valve 11 is in intermediateposition, so that the full water pressure available in the chamber 2`enters the low pressure chamber 15. Consequently the diaphragm 5 isforced downwards whereby on the one hand the gas valve 24 is closedimmediately and a larger flow section is made available by theregulatorvalve 3.` When the gas burner 25 is extinguished, an increasedflow of Water takes place until the tap valve 11 `is completely closedand the valve body 18 is pressed on-the seat 20. This increased now ofwater taking place when the` burner is already extinguished eliminatesthe heat stored in the heating unit 9, so that after-heating of hotwater is avoided.

in Fig. 2 the diaphragm housing of the water deficiency safety devicehas been represented separately. water pressure arises in the lowpressure chamber 15, the diaphragm 5 would curve strongly downwards andcontact the wall of the lower chamber (dynamic pressure chamber 4)thereby closing more or less the orifice of the supply conduit 6. Inorder to prevent such a contact of the diaphragm 5 with the wall of thelower chamber, a supporting surface 23 having the shape of a plate isprovided in the dynamic pressure chamber -4. The valve body 3 penetratesthe plate member 23. The water can therefore ow in undisturbed mannerfrom the regulator valve 3 through the supply conduit 6 tothe Venturitube 7 even if the diaphragm 5 is curved downwards.

ln the embodiment represented in Fig. 3, cold water enters in thedirection of the arrow 25, passes through a throttling point 26, then,as has been signified by the strokedotted line, flows through a heatingunit (not represented `in the drawing) and finally appears as hot waterin the tap conduit 27. A cold water draw-off valve 28 and a hot waterdraw-off -valve 29 form a-mixing battery having a dischargeAdesignatedwbypthe purper-af,

Consequently, the connecting channel 16, 16 'is If the full 30. Thediaphragm switch 31 of the water deficiency safety device is connectedat both sides'to the throttling point 26 by means of the channels 32,33. The diaphragm 31' of the water deficiency safety device 31 is inknown manner lifted by means of the dynamic pressure difference arisingat the throttling point 26, a not represented burner gas valve beingopened thereby by means of a push rod 34. This burner gas valve closesagain automatically under the influence of the valve spring when thepressure difference is equalized. A channel 36 connects the dynamicpressure chamber 35 of the diaphragm switch 31 with the draw-off conduit27, the channel 36 having its end closely arranged above the valve seatof the draw-off valve 29. The mouth of the channel 36 is governed by atubular valve slide 37 which is fastened by means of bridges 37 to thespindle 38 of the draw-off valve 29. When the draw-otf valve 29 isopened, the valve slide 37 closes the mouth of the channel 36 withoutthereby hindering the flow-out of hot water from the draw-off conduit27. Consequently, the pressure difference can be produced which operatesthe diaphragm switch 31 so as to perform an opening movement of the gasvalve.

During the locking motion of the draw-olf valve 29, the valve slide 37opens the mouth of the channel, thus permitting the dynamic pressure ofthe chamber 35 to equalize through the channel 36. Therefore, thepressure difference effective at the diaphragm switch 31 is alreadyeliminated before the Waterflow is interrupted by the owoff valve 29.The gas burner therefore already -extinguishes during the beginningtofthe locking motion of the flow-off valve. 29, so that Water still flowsthrough the apparatus when the burner is-extinguished and absorbs thestored heat of the heating unit. The flow of water comes to an end onlywhen the draw-olf valve,.29 has reached its seat.

What we claim is:

1. Gas water heater of continuous ow type comprising in combination: aheating unit having a ow system, a gas burner for heatingthe heatingunit, a spring-weighed gas valve controlling the gas supply to theburner, a drawoff valve for closing theiiow system, a throttle bodybeing built in the flow system and dividing said system into a dynamicpressure area and a low pressure area, a housing, a motion memberdividing said housing into two chambers, said motion member acting uponthe gas valve, by means of junction channels, one of said chambers beingconnected to said dynamic pressure area and the other of said chambersbeing connected to said low pressure area of the flow system, a valvelocked by-pass channel connecting the dynamic pressure area and the lowpressure area of theowsystem with each other by-passing thc throttlebody, and means adapted to open the valve being located in the by-passchannel while being dependent on the closing motion of said draw-offvalve.

2. Gas water heater of continuous ow type comprising in combination: aheating unit having a iiow system, a gas burner for heatingthe heatingunit, a spring-weighed gas valve controlling the gas supply to theburner, a drawot valve for closing the flow system, a throttle bodybeing built in the flow system and dividing said system into a dynamicpressure area, and a low pressure area, a housing, a motion memberdividing said housing into two chambers, said motion member acting uponthe gas valve, by means of junction channels, one of said chambers beingconnected to said dynamic pressure area and the other of said chambersbeing connected to said low pressure area of the flow system', a checkvalve with one by-pass being interposed as slow-acting ignition valve inone of said connection channels, a valve locked by-pass channelconnecting thedynamic .pressure area and the low pressure area of theflow system with each other by-passing the throttle pointl and saidreturn valve, and means adapted to open theV valve being located in theby-pass channelwhile being dependent on the locking motion of ,saiddraw-off valve.

3. Gas water heater of continuous flow type comprising in combination: aheating unit having a ow system, a gas burner for heating the heatingunit, a spring-weighed gas valve controlling the gas supply to theburner, a drawoi valve for closing the flow system, a throttle bodybeing built in the flow system and dividing said system into a dynamicpressure area, and a low pressure area, a housing, a motion memberdividing said housing into two chambers, said motion member acting uponthe gas valve, by means of junction channels, one of said chambers beingconnected to said dynamic pressure area and the other of said chambersbeing connected to sai-d low pressure area of the tlow system, aregulator valve being located in the junction channel leading to thechamber of dynamic pressure, said regulator valve being controlled bysaid motion member, a check valve with one by-pass interposed in thejunction channel leading to the low pressure chamber, a bypass channelwhich on the one side, when viewed in the direction of flow, isconnected to the ilow system in front of said regulator valve andby-passing the throttle body and the return valve is led to the lowpressure chamber, a closing valve being in said by-pass channel, andmeans adapted to open said closing valve while being dependent on thelocking motion of said ow-off valve.

4. Gas water heater of the continuous flow type according to claim 3,said closing valve being designed as double seat valve and beingconnected with the flow-oi vaive in this manner that the double seatvalve as well with closed as with opened dow-olf valve remains closedand only is opened during closing motion of the ow-off valve.

5. Gas water heater of the continuous flow type comprising incombination: a heating unit having a ilow system, a gas burner forheating of the heating unit, a springweighed gas valve controlling thegas supply to the burner, a draw-orf valve for closing the ow system, athrottle body being built in the ow system and dividing said system intoa. dynamic pressure area and a W pressure area, a housing being providedwith connecting orifices, a diaphragm being connected with the gas valveand dividing said housing into two chambers, by means of junctionchannels running into the connecting orifices one of the chambers beingconnected to the low pressure area, the other chamber being connected tothe dynamic pressure area, a supporting member for the diaphragm beingarranged inthe chamber of dynamic pressure with distance from thewalling of the housing which has been provided with connecting orices, aregulator valve being controlled by said diaphragm, said regulator valvepenetrating said supporting member and cooperating with one of saidconnecting orifices, a by-pass channel being connected, when viewed inthe direction of flow, on its one side in front of said regulator valveto the ow system, and by-passing the throttle body is led to the lowpressure chamber, a closing valve being provided in said by-passchannel, and means adapted for opening of said closing valve while beingdependent on the closing motion of said dow-off valve.

6. Gas water heater of continuous ow type comprising in combination: aheating unit having a ow system, a gas burner for heating the heatingunit, a spring-weighed gas valve controlling the gas supply to theburner, a drawoff valve for closing the flow system, a throttle bodybeing built in the ow system and dividing said system into a dynamicpressure area and a low pressure area, a housing, a motion memberdividing said housing into two chambers, said motion member acting uponthe gas valve, by means of junction channels, one of said chambers beingconnected to said dynamic pressure area and the other of said chambersbeing connected to said low pressure area of the iiow system, a valvelocked by-pass channel being led from the chamber of dynamic pressureclosely to the connecting point of the draw-off valve, said draw-ottvalve being arranged at the discharge end of the flow system, and meansadapted to open the valve in the by-pass channel while being dependenton the closing motion of the draw-olf valve.

References Cited in the le of this patent UNITED STATES PATENTS

